Voice or speech recognition systems (e.g., an interactive voice response (IVR) system) may be used for a variety applications, such as voice dialing (e.g., “call home”), call routing (e.g., “I would like to make a collect call”), data entry (e.g., entering a credit card number), preparation of structured documents (e.g., a report), content-based spoken audio search (e.g., find a song when particular words were spoken), etc. IVR generally refers to a computerized system that allows a user, typically a telephone caller, to select an option from a voice menu or otherwise interface with a computer system. Generally, the system plays pre-recorded voice prompts to which the user responds by either pressing a number on a telephone keypad or speaking to the system.
The success of a voice recognition application may depend on how rigorously a speech application has been tested. However, user inputs (e.g., spoken words or voice recognition entries) to the voice recognition application may change from time to time. This may cause the voice recognition application to be less efficient and less accurate as time passes.